ESPN Tennis

LOS ANGELES -- Tommy Haas, Sam Querrey, Donald Young, Ashley Harkleroad and Alexandra Stevenson are among those entered in Sunday's inaugural Shotgun 21 World Championships, a tennis competition where men and women will play each other.

The one-day tournament in suburban Pacific Palisades offers a purse of more than $20,000 in prize money, with $10,000 and a limited edition Fender Stratocaster going to the winner.

Tournament founder/director Steve Bellamy said the event will have a 32-player main draw, and should be completed in about three hours. He said a committee examined the value and qualifications of every entrant and choose the top 28. The other four will come from a qualifier earlier in the day at the Palisades Tennis Center that's open to the public.

There are four significant rule changes from traditional tennis: no overhand serve, second serves or lets, and the winner is the first to reach 21 points as opposed to deuce/ad scoring. All serving is drop-hit and struck from below the waist.

"The player field for this event is flat-out amazing," Bellamy said. "Even the celebrities playing are incredible."

They include Gavin Rossdale, the founder and lead singer of the band "Bush," and husband of entertainer Gwen Stefani; actor/model Boris Kodjoe, and actress/model Sara Foster, Haas' girlfriend.

Haas, ranked as high as No. 2 in the world, lost to Wimbledon champion Rafael Nadal 6-4, 7-6 on Thursday night in the Cincinnati Masters tournament and is considered one of the favorites.

Querrey is the third-ranked male in the United States; Harkleroad is the fifth-ranked woman, and Stevenson is in the midst of a comeback after a shoulder injury. She reached the Wimbledon semifinals as an 18-year-old unknown in 1999.

The first tournament where men and women play each other recalls the 1973 exhibition match between Billie Jean King and Bobby Riggs. King, at the top of her game, won easily against her long retired opponent.

"Women traditionally keep the ball in play longer and are very solid off the ground," Bellamy said. "So you take the serve out of the equation, and you really have a leveling of the playing field."

Copyright 2008 by The Associated Press